With reference to the negative feedback system shown in the figure above, which of the following descriptions best describes the receptors (marked A in the figure) used to detect decreases in blood calcium concentrations? 
Definitions:
Reflexive Processes
Cognitive operations and behaviors that occur automatically without conscious deliberation.
Dual Process Approach
A theory proposing that human cognition operates through two distinct types of processes: automatic, intuitive thinking (System 1), and deliberate, analytical reasoning (System 2).
Process 1
Often referred to as the initial, automatic, and intuitive response or thought process that occurs without deliberate analytical effort.
Biases
A tendency or partiality that favors or discriminates against something, someone, or a group over another, often in a manner deemed to be unjust.
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